1. Field of the Invention
The present invention relates to improvements in water ring type vacuum pumps.
2. Description of the Prior Art
In the water ring type vacuum pump, as is well known, sealing water within the pump chamber is rotated by an impeller so as to be moved radially of the impeller, whereby air is sucked and discharged. An example of the conventional water ring type vacuum pump is shown in FIG. 7. As an impeller 32 provided in a pump chamber 31 rotates, air sucked through an inlet 33 is discharged through an outlet 34 via the pump chamber 31. Sealing water is fed through a water inlet 35. The fed sealing water flows into the pump chamber 31 through a clearance between the inner wall surface of the pump chamber 31 and both side faces of the impeller 32, and thereafter is discharged through the outlet 34 along with air.
In this conventional sealing-water feeding construction, a greater clearance between the inner wall surface of the plump chamber 31 and both side faces of the impeller 32 would more often cause the air to leak through the clearance, resulting in a deteriorated pump performance. Also, even if the clearance is small, a small amount of water feed would lead to insufficient sealing performance of the water of the clearance between the inner wall surface of the pump chamber 31 and both side faces of the impeller 32. This also would result in a deteriorated pump performance.